Device for supplying fuel for a rocket propulsion unit and heat exchanger to be used in said device

ABSTRACT

Device for supplying fuel for a rocket propulsion unit has a first and at least a second fuel circuit for respective different fuels. Each fuel is brought to an increased energy level by a pump and is supplied for combustion by way of injection elements. The first fuel is heated in cooling channels extending in a propulsion chamber wall before the fuel is supplied for combustion, and the first fuel is subsequently fed to at least the turbines assigned to the pumps. A heat exchanger is provided in which the fuel coming from the turbines is in a heat exchange with a fuel coming from a pump. A heat exchanger especially usable in the device for supplying fuel is provided.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a device for supplying fuel for a rocketpropulsion unit, particularly for a rocket propulsion unit which isbased on the combustion of hydrogen and oxygen in the expander circuit,as well as to a heat exchanger to be used in said device for supplyingfuel.

For the injection of hydrogen and oxygen into the propulsion chamber ofa rocket, the fuel situated in the tanks, for example, hydrogen andoxygen, must be fed at high pressure in a controlled manner. In thiscase, the hydrogen is first guided by way of control valves into thearea outside the propulsion chamber so that, on the one hand, thehydrogen causes a cooling of the combustion chamber wall and, on theother hand, in the case of the expander circuit, because of the heatgenerated by the combustion events in the combustion chamber, thehydrogen itself is heated for the later expansion in turbines. At acorresponding temperature of the hydrogen, the latter can drive turbineswhich, in turn, cause the driving of pumps for feeding hydrogen andoxygen to the injection elements at a sufficient pressure. In order toreach a combustion chamber pressure in the rocket propulsion unit whichis as high as possible, it is required that devices of this type have amore efficient method of operation.

From the state of the art reflected in U.S. Pat. Nos. 3,049,870;5,410,874; and 4,583,362 it is known to provide a heat exchanger with arocket propulsion system, in which the fuel from a turbine exchangesheat with fuel from a pump in order to achieve a further heating of thefuel. However it is problematical with this state of the art in that, inspite of the additional heating, under the circumstances there thedesired combustion chamber pressure is not achieved and furthermore thearrangement requires a relatively large space.

It is therefore an object of the invention to provide an optimumarrangement for supplying fuel for a rocket propulsion unit with anexpander circuit which, as a whole, operates more efficiently andincreases the combustion chamber pressure for rocket propulsion units.

This object is achieved by a device for supplying fuel for a rocketpropulsion unit having a first and at least a second fuel circuit, eachfuel being brought to an increased energy level by means of a pump andbeing supplied for combustion by way of injection elements, the firstfuel being heated in cooling channels extending in a propulsion chamberwall before the fuel is supplied for combustion, and the first fuelsubsequently being fed to at least the turbines assigned to the pumps,characterized in that a heat exchanger is provided in which the fuelcoming from the turbines is in a heat exchange with a fuel coming from apump. Alternative embodiments are described in the claims.

In the following, the invention will be described by means of theattached FIGS. 1 to 3.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a rocket propulsion unit with an expander circuitaccording to the prior art;

FIG. 2 is a view of the device according to the invention for supplyingfuel and having a heat exchanger; and

FIG. 3 is a schematic sectional view of the embodiment of the heatexchanger of FIG. 2 according to the invention, in contrast to FIG. 2,the heat exchanger being arranged in the injection head and beingintegrated with the injection elements of the combustion chamber.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a device for supplying fuel according to the prior art.This device is arranged between a hydrogen tank 1 and an oxygen tank 2on one side and a propulsion chamber 3 on the other side. The device forsupplying fuel is controlled by a central governor 5 which, in turn, byway of corresponding pipes, controls a hydrogen governor 6 forcontrolling the hydrogen circuit 6 a and an oxygen governor 7 forcontrolling an oxygen circuit 7 a. The hydrogen governor 6 controls atank valve (isolation valve) 11 by means of which the feeding of liquidhydrogen from the hydrogen tank 1 to a hydrogen pump 12 is caused orprevented. In the embodiment according to FIG. 1, the hydrogen pump 12is constructed as a two-stage pump and therefore comprises a first setof impellers 13 and a second set of impellers 14 in order to pressurizethe hydrogen. The hydrogen leaves the hydrogen pump 12 by way of a pipe15 through which the hydrogen is fed to the cooling channels 16. Thecooling channels 16 extend essentially in the axial direction at leastin the area of the combustion chamber wall 17 which bounds thecombustion space 19 and the first portion of the expansion nozzle 20, aswell as partially also in the area of a nozzle extension wall 21. Inthese areas, the hydrogen is used for cooling the corresponding walls.Simultaneously, the hydrogen is heated. Subsequently, the hydrogen isfed by way of a pipe 23 to the turbine 24 which drives the hydrogen pump12. By way of a manifold, the hydrogen arrives in the area of a turbinewheel which is connected with the impellers 13, 14 of the hydrogen pump12. The hydrogen, which, as a result of its heating, is at a raisedtemperature, thereby drives the turbine 24 and thus the hydrogen pump12.

The drive of the turbine 24 causes a drop in pressure and temperature inthe hydrogen which is supplied by way of a pipe 27 to the turbine 28 ofan oxygen pump 29. The turbine 28 drives the oxygen pump 29, wherebyoxygen from the oxygen tank 2 is supplied to the oxygen pump when thetank valve (isolation valve 11) assigned to the oxygen pump 29 is open.As a result of the drive of the turbine 28, the hydrogen experiencesanother pressure and temperature drop and is subsequently supplied byway of a pipe 31 to the injection head 32 with the injection elements33. On the other hand, the oxygen under pressure by means of the oxygenpump 29 arrives by way of a pipe 34 from the pump 29 also at theinjection head 32. The propulsion chamber formed of the injection head32, the combustion chamber 17 and the nozzle extension 21 extends fromthe injection head 32. The liquid oxygen and the liquid hydrogentherefore arrive in the combustion chamber on different paths by way ofinjection elements 33. The hydrogen-oxygen mixture is ignited by anigniter 36 in order to cause the propulsion of the rocket. Thecontrolling of the hydrogen circuit 6 a takes place by way of valves 42,43 which are controlled by the hydrogen governor 6. The oxygen circuit 7a is controlled by way of valves 44, 45 which are partially controlledby the central governor 5 and partially by the oxygen governor 7.

Thus, in the case of the fuel supply device according to the prior art,the hydrogen heated in the propulsion chamber wall 17 and 21 is fed tothe turbines 24, 28 for driving the respective pumps 12, 29.Subsequently, the hydrogen arrives directly at the injection head 32 inorder to be supplied by it to the combustion in the combustion space 19,20.

FIG. 2 shows the device for supplying fuel according to the invention.Elements of this representation or components of this device which, withrespect to their function, correspond to elements of FIG. 1 or of theprior art illustrated there or are similar to them have the samereference numbers in FIG. 2. The connection of the control valvesillustrated in FIG. 2 with the corresponding control unit as well as thecontrol units themselves are illustrated in FIG. 2.

The hydrogen discharged by the hydrogen pump 12 by way of the pipe 15does not arrive directly in the area of the propulsion chamber wall 17but is first fed to a heat exchanger 100. For controlling the amount ofthe hydrogen fed to the latter, the control valve 42 is provided betweenthe hydrogen pump 12 and the heat exchanger 100. The heat exchanger 100has an inlet pipe 101 for the hydrogen coming from the hydrogen pump 12.After flowing through a first heat exchanger space 103, the hydrogenflows out of the heat exchanger 100 through a first outlet pipe 105.From there, the hydrogen is guided by way of a pipe 15 b into the areaof the injection head 32, from where it arrives in the cooling channels(not shown) of the combustion chamber wall 17. The cooling channelsextend preferably in the axial direction in the combustion chamber wall17. As a result, on the one hand, the combustion chamber wall 17 iscooled during the combustion events and, on the other hand, the hydrogenis acted upon by a higher temperature in order to drive the turbine 24of the hydrogen pump 12 and the turbine 28 of the oxygen pump 29. Thepump pressures are sufficiently high for overcoming losses of otherconsuming devices, such as the injection elements 33, the piping or thecooling channels, and finally have a sufficient pressure for theinjection operation which, in a predetermined manner, must be greaterthan the combustion chamber pressure.

From the cooling channels, the hydrogen reaches the turbine 24 by way ofthe line 23 in order to drive the hydrogen pump 12. From there, thehydrogen arrives by way of a pipe 27 at the turbine 28 of the oxygenpump 29. In contrast to the object illustrated in FIG. 1, the hydrogendoes not arrive from the turbine 28 directly at the injection head 32,but by way of a pipe 31 a and a second inlet pipe 107 first arrives atthe heat exchanger 100. By way of a second outlet pipe 109, the hydrogenexits the heat exchanger 100 and is supplied to the injection head 32 byway of a pipe 31 b. After the entry of the hydrogen through the secondinlet pipe 107 into the heat exchanger 100, the hydrogen will flowthrough a second heat exchanger space 111.

In the heat exchanger 100, as a result of a heat transfer, heat istransferred from the hydrogen, which is heated in the cooling channelsof the propulsion chamber wall 17 and which arrives in the heatexchanger 100 through the second inlet pipe 107, to the hydrogen whichcomes from the hydrogen pump 12, flows through the first heat exchangerspace 103 and then is to be supplied to the cooling channels. As aresult, the hydrogen, which leaves the first heat exchanger space 103 byway of the first outlet pipe 105 and is thereby supplied to the coolingchannels, receives a higher temperature than provided in the objectaccording to the prior art illustrated in FIG. 1. Although, as a result,the cooling of the propulsion chamber wall 17 takes place at anoperating point which is higher in comparison to the prior art, that is,at a higher temperature of the hydrogen, the required cooling effect canbe compensated by means of a corresponding design of the coolingchannels. The hydrogen leaves the cooling channels through the pipe 23and, in this case, has a higher temperature than in the prior art. Whenflowing through the second heat exchanger space 111, the hydrogen heatedin the cooling channels delivers heat to the hydrogen flowing throughthe first heat exchanger space 103, which hydrogen is then fed to theinjection head 32 for the combustion with oxygen.

After exiting from the cooling channels, the hydrogen has a highertemperature than in the prior art. As a result, the energy charged intothe turbine 24, 28 becomes higher than in the prior art, so that, withthe increase of the pumping capacity of the pumps 12, 29, a highercombustion chamber pressure is reached and the entire rocket propulsionunit will therefore operate with a better specific impetus.

In the case of the object illustrated in FIG. 2, the control valves 42,43, 44, 45 for the hydrogen circuit 6 a and for the oxygen circuit 7 aare arranged in a manner similar to that of the prior art. The pipe orvalve arrangement can also be implemented in other variants. It isimportant in this case that the heat exchanger 100 preheats a fuelwhich, before the injection, is provided for the cooling and for drivingthe turbines, in order to operate the turbines at a higher energy level.

The heat exchanger 100 can optionally be arranged on the injection head32 or can be integrated with the latter to a unit or arrangement. Thisvariant is schematically illustrated in FIG. 3.

The cold hydrogen, which, by way of the first inlet pipe 101, arrives inthe heat exchanger 100, therefore flows through the first heat exchangerspace 103 and leaves the latter by way of the pipe 15 b. As illustratedin FIG. 3, the first heat exchanger space 103 may comprise severalpartial spaces. Thus, the first heat exchanger space 103 may comprise apartial space 141, a partial space 142 and additionally a heat exchangefinger 143 or a combination thereof. A connection pipe 147 connects theinterior of the first partial space 141 with the interior of the secondpartial space 142, from where the hydrogen leaves the first heatexchanger space 103 by way of the first outlet pipe 15 b.

In FIG. 3, an injection element 33 for injecting hydrogen into thecombustion chamber 19 is illustrated as an example. For a case in whichthe heat exchanger 100 is arranged on or in the injection head 32, theheat exchange fingers 143 can be provided. These are preferably arrangedsuch that they project from the second partial space 142 into thecombustion chamber 19. In an advantageous further development of theheat exchanger 100, the connection pipe 147 extends through the interiorof the second partial space 142 and into the heat exchange finger 143 toclose to the closed end 144 of the latter. In the area of the closed end144, the hydrogen, which is at first guided in the connection pipe 147,leaves the connection pipe 147 and arrives in the space 145 between theouter contour of the connection pipe 147 and the inner contour of theheat exchange finger 143. In the space 145, the hydrogen flows back intothe direction which is opposite to the direction in which the hydrogenflows in the connection pipe 147. From the space 145, the hydrogenarrives in the second partial space 142 in order to leave the latterthrough one or several outlet pipes 15 b. From there, the hydrogenarrives by way of the pipe 15 b in the cooling channels 16. According tothe prior art, several cooling channels 16 can be arranged such that thehydrogen flows in the combustion chamber wall 17 in a counterflowprocess, that is, in the opposite direction with respect to thecombustible gases.

The warm hydrogen supplied to the heat exchanger 100 by way of thesecond inlet pipe 107 arrives in the second heat exchanger space 111which, in turn, may be formed of several partial spaces. In theembodiment according to FIG. 3, the second heat exchanger space 111comprises only one space 152.

From the space 152, the warm hydrogen arrives at the injection elements33. For this purpose, the connection pipes 153 are provided which leadfrom the space 152 to the injection elements 33. The connection pipes153 can change directly into the respective injection element 33. Also,in an arrangement according to FIG. 3, the connection pipe 153 canproject through the two partial spaces 141, 142 of the first heatexchanger space 103 as well as the oxygen space 151.

The liquid oxygen from the pump 29 enters by way of the pipe 34 into thespace 151. With approximately 100 K, its temperature is higher than thatof the cold hydrogen in space 103, which measures approximately 45 K.Warm currents 161, 162 and 167 therefore flow from the warmer oxygen inspace 151 onto the colder hydrogen in space 103 or the partial spaces141 and 142 as well as through the walls of the tubes 147 withoptionally arranged heat exchange ribs onto the hydrogen guided there.

The partial spaces 141, 142 as well as 151, 152 illustrated in FIG. 3can partially also have a rotationally symmetrical design. Furthermore,the connection pipes 147, 153 may also be provided with heat exchangeribs 147 a and 153 a respectively. Such heat exchange ribs may also beprovided at other points of the heat exchanger 100. The heat exchangeribs 147 a are preferably arranged in the area of the oxygen space 151,while the heat exchange ribs 153 a are preferably arranged in the areaof the first partial space 141 of the first exchanger space 103.

The oxygen space 151 is preferably situated between the first partialspace 141 and the second partial space 142 of the first heat exchanger103. In this case, their contour surfaces are arranged such with respectto one another that a heat transfer 161 takes place from the firstoxygen space 151 to the first partial space 141. Furthermore, a heattransfer 162 takes place from the oxygen space 151 into the interior ofthe connection pipe 147 which is connected with the interior of thefirst partial space 141.

Also, in the arrangement according to FIG. 3, a heat transfer 165 takesplace from the second heat exchanger space 111 to the first partialspace 141 of the first heat exchanger space 103. In addition, from theinterior of the pipe 153, a heat transfer 166 takes place to the firstpartial space 141.

Furthermore, a heat transfer 167 takes place from the oxygen space 151to the second partial space 142 of the first heat exchange space 103. Inthe arrangement of FIG. 3, on the one hand, a heat transfer 168 takesplace from the combustion chamber 19 in the direction of the interior ofthe partial space 142 and a heat transfer 169 to the space 145 of theheat exchange fingers 143, as well as a heat transfer 170 through thecombustion chamber wall to the hydrogen in the cooling channels 16.

The heat exchanger 100 according to the embodiment illustrated in FIG. 3therefore permits a heating-up of the fuel coming by way of the pipe 15and the first inlet pipe 101 from the hydrogen pump 12 on the basis ofthe heat transfers 161, 162, 168, 169 in the first heat exchanger space103, from where the fuel arrives at the cooling channels 16. Therefore,when entering into the cooling channels 16, the fuel has a highertemperature than in the prior art. The fuel therefore leaves the coolingchannels 16 by way of the pipe 23 also at a higher temperature than inthe state of the art, so that more energy is available for operating theconsuming devices of the device for supplying fuel. As a result, ahigher combustion chamber pressure can be achieved which permits abetter specific impetus.

The invention was described for a rocket propulsion unit using the twofuels hydrogen and oxygen. However, the invention can also be usedgenerally for a first and a second fuel and even for additional fuels.It is only important that the fuel provided for driving the turbines, asa result of the heat exchange with the fuels, which are injecteddirectly, is heated up higher and thus permits a higher turbine output,a higher pump pressure and thus a higher combustion chamber pressure.

What is claimed is:
 1. A device for supplying fuel for a rocketpropulsion unit having a first fuel circuit with a first fuel and atleast a second fuel circuit with a second fuel, each fuel being broughtto an increased energy level by a pump and being supplied for combustionover an injection head with injection elements, the first fuel beingheated in cooling channels extending in a propulsion chamber wall beforethe fuel is supplied for combustion, and the first fuel subsequentlybeing fed to at least turbines assigned to the pumps, wherein a heatexchanger is provided in which fuel coming from the turbines is in aheat exchange with fuel coming from a pump, wherein the heat exchangeris one of arranged on the injection head and integrated as a unit withthe injection head, wherein the heat exchanger comprises a first, asecond and a third inlet pipe as well as a first and at least a secondoutlet pipe, the first inlet pipe leading into a first heat exchangerspace which in a heat-conducting manner is connected with a second heatexchanger space, fuel arriving from the first heat exchanger space byway of the first outlet pipe arriving at the cooling channels and fuelarriving by way of the second inlet pipe in the second heat exchangerspace being connected with the injection head at least by way of thesecond outlet pipe, and wherein the first heat exchanger space isconnected with at least one heat exchange finger which projects at leastpartially into a combustion chamber and whose discharge is connectedwith the first outlet pipe.
 2. A device according to claim 1, whereinthe first heat exchanger space is formed by a first partial space and asecond partial space which are connected by way of a connection pipe,the second heat exchanger space being connected by way of connectionpipes with the combustion chamber, and a third heat exchanger spacebeing situated in an area between the first partial space and the secondpartial space of the first heat exchanger space and being connected byway of connection pipes with the combustion chamber.
 3. A deviceaccording to claim 2, wherein the second fuel is fed to the third heatexchanger space and the first fuel is introduced into the second heatexchanger space from an area which, viewed in a flow direction, issituated behind a last turbine.
 4. A device according to claim 1,wherein said fuels are hydrogen and oxygen.
 5. A device for supplyingfuel for a rocket propulsion unit having a first fuel circuit with afirst fuel and at least a second fuel circuit with a second fuel, eachfuel being brought to an increased energy level by a pump and beingsupplied for combustion over an injection head with injection elements,the first fuel being heated in cooling channels extending in apropulsion chamber wall before the fuel is supplied for combustion, andthe first fuel subsequently being fed to at least turbines assigned tothe pumps, wherein a heat exchanger is provided in which fuel comingfrom the turbines is in a heat exchange with fuel coming from a pump,wherein the heat exchanger is one of arranged on the injection head andintegrated as a unit with the injection head, wherein the heat exchangercomprises a first, a second and a third inlet pipe as well as a firstand at least a second outlet pipe, the first inlet pipe leading into afirst heat exchanger space which in a heat-conducting manner isconnected with a second heat exchanger space, fuel arriving from thefirst heat exchanger space by way of the first outlet pipe arriving atthe cooling channels and fuel arriving by way of the second inlet pipein the second heat exchanger space being connected with the injectionhead at least by way of the second outlet pipe, and wherein the firstheat exchanger space is formed by a first partial space and a secondpartial space which are connected by way of a connection pipe, thesecond heat exchanger space being connected by way of connection pipeswith a combustion chamber, and a third heat exchanger space beingsituated in an area between the first partial space and the secondpartial space of the first heat exchanger space and being connected byway of connection pipes with the combustion chamber.
 6. A deviceaccording to claim 5, wherein the second fuel is fed to the third heatexchanger space and the first fuel is introduced into the second heatexchanger space from an area which, viewed in a flow direction, issituated behind a last turbine.
 7. A heat exchanger for a rocketpropulsion unit having: a combustion space bounded by propulsion chamberwalls, cooling channels in said chamber walls, an injection head, afirst fuel circuit for supplying a first fuel to the injection head, asecond fuel circuit for supplying a second fuel to the injection head,wherein said fuel circuits include pumps driven by turbines, whereinsaid first fuel in said first fuel circuit is heated by the coolingchannels and fed to the turbines before being supplied to the injectionhead, said heat exchanger being operable to exchange heat between fuelfrom the turbines and fuel from a pump, said heat exchanger comprising:a first, a second and a third inlet pipe as well as a first and at leasta second outlet pipe, the first inlet pipe leading into a first heatexchanger space which in a heat-conducting manner is connected with asecond heat exchanger space, fuel arriving from the first heat exchangerspace by way of the first outlet pipe arriving at the cooling channelsand fuel arriving by way of the second inlet pipe in the second heatexchanger space being connected with the injection head at least by wayof the second outlet pipe, wherein the first heat exchanger space isconnected with at least one heat exchange finger which projects at leastpartially into a combustion chamber and whose discharge is connectedwith the first outlet pipe.
 8. A heat exchanger for a rocket propulsionunit having: a combustion space bounded by propulsion chamber walls,cooling channels in said chamber walls, an injection head, a first fuelcircuit for supplying a first fuel to the injection head, a second fuelcircuit for supplying a second fuel to the injection head, wherein saidfuel circuits include pumps driven by turbines, wherein said first fuelin said first fuel circuit is heated by the cooling channels and fed tothe turbines before being supplied to the injection head, said heatexchanger being operable to exchange heat between fuel from the turbinesand fuel from a pump, said heat exchanger comprising: a first, a secondand a third inlet pipe as well as a first and at least a second outletpipe, the first inlet pipe leading into a first heat exchanger spacewhich in a heat-conducting manner is connected with a second heatexchanger space, fuel arriving from the first heat exchanger space byway of the first outlet pipe arriving at the cooling channels and fuelarriving by way of the second inlet pipe in the second heat exchangerspace being connected with the injection head at least by way of thesecond outlet pipe, wherein the first heat exchanger space is formed bya first partial space and a second partial space which are connected byway of a connection pipe, the second heat exchanger space beingconnected by way of connection pipes with a combustion chamber, and athird heat exchanger space being situated in an area between the firstpartial space and the second partial space of the first heat exchangerspace and being connected by way of connection pipes with the combustionchamber.
 9. The heat exchanger according to claim 8, wherein the secondfuel is fed to the third heat exchanger space and the first fuel isintroduced into the second heat exchanger space from an area which,viewed in a flow direction, is situated behind a last turbine.